Black Friday: lifetime access is on a special offer in the app, until November 30. Black Friday: special offer on lifetime access, until November 30. Download
생활하수는 환경 오염의 주요 원인 중 하나입니다.saenghwalhasuneun hwangyeong oyum-ui juyo wonin jung hanamida.Domestic wastewater is one of the main causes of environmental pollution.